Improvement in electric alarms



F. L. POPE.

Electric-Alarms.

Patented Feb. 24,1874.

Inventor UNITED STATES PATENT OFFICE.

FRANK L. POPE, OF ELIZABETH, NEW JERSEY.

IMPROVEMENT IN ELECTRIC ALARMS.

Specification forming part of Letters Patent No. 147,975, dated February 24, 1874 application tiled January 14, 1874.

To all whom it may concern:

Be it known that I, FRANK L. POPE, of Elizabeth, New Jersey, have invented an Improved Device for Operating Electric Alarms, of which the following is a specification:

The object of my invention is to provide means whereby an ordinary vibrating or self-breaking electric alarm may be set in action by the interruption of an electric circuit, without the intervention of a relay or of a secondary battery.

In the accompanying drawing, the electromagnet E is provided with an armature, A, movable upon the pivot to, its other extremity being armed with a hammer, H, which strikes against the bell B whenever the magnet attracts its armature. Then the magnet M releases the armature, the latter is drawn back by the spiral springO until it strikes the fiat spring S. From one pole of the battery E a wire, 1, is connected-t0 the spring S. A second wire, 5, connects the armature A with the helices of the magnetM, and a third wire, 6 6, connects'the said helices with the other pole of the battery. V hen the armature A falls back against the spring S, the circuit is completed, and the magnet M attracts the armature and sounds the bell; but, the circuit being now broken between A and S, the armature again falls back and restores the connection, and thus a continuous and rapid succession of strokes is given upon the bell B.

The alarm may be set in action or stopped at plea-sure by closing or opening the switch WV.

The above-described devices are old and in common use, and, taken by themselves, form no part of my invention.

My improvement consists in combining with the hereinbefore-described apparatus a shuntcircuit, 2 3 4, which may be provided with keys or circuit-breakers K K, and so arranged that the said shunt-circuit, when closed, forms a connection between the armatureA and the spring S, when they are not themselves in contact, and when the armature is drawn up to the m agnet M, by which means the arm ature is retained in that position and prevented from falling back until the circuit 2 3 4. is broken by means of one of the circuit-breakers K or K, or otherwise. Thus it will be understood that a continuous alarm will be sounded during the time the circuit 2 3 4 is broken, and the switch V at the same time closed, and not otherwise.

A galvanometer or other suitable currentindicator, G, is pla ed at some point in the circuit, by which the condition of the battery E or strength of the current may be known.

I claim as my invention 1. The combination of a Vibrating or selfbreaking electric-alarm apparatus with a shunt circuit, arranged and operated substantially as herein specified.

2. The combination of a vibrating or selfbreaking electric alarm apparatus, a galvanometer, and a switch (either or both) with a shuntcireuit, arranged and operated substantially as and for the purpose specified.

Signed by me this 17th day of December, 1873.

FRANK L. JPOPE.

WVitnesscs:

J. N. ASHLEY, STEPHEN G. HENDmoKsoN. 

